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Bergmann R, Kubeil M, Zarschler K, Chhabra S, Tajhya RB, Beeton C, Pennington MW, Bachmann M, Norton RS, Stephan H. Distribution and kinetics of the Kv1.3-blocking peptide HsTX1[R14A] in experimental rats. Sci Rep 2017. [PMID: 28623364 PMCID: PMC5473807 DOI: 10.1038/s41598-017-03998-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The peptide HsTX1[R14A] is a potent and selective blocker of the voltage-gated potassium channel Kv1.3, which is a highly promising target for the treatment of autoimmune diseases and other conditions. In order to assess the biodistribution of this peptide, it was conjugated with NOTA and radiolabelled with copper-64. [64Cu]Cu-NOTA-HsTX1[R14A] was synthesised in high radiochemical purity and yield. The radiotracer was evaluated in vitro and in vivo. The biodistribution and PET studies after intravenous and subcutaneous injections showed similar patterns and kinetics. The hydrophilic peptide was rapidly distributed, showed low accumulation in most of the organs and tissues, and demonstrated high molecular stability in vitro and in vivo. The most prominent accumulation occurred in the epiphyseal plates of trabecular bones. The high stability and bioavailability, low normal-tissue uptake of [64Cu]Cu-NOTA-HsTX1[R14A], and accumulation in regions of up-regulated Kv channels both in vitro and in vivo demonstrate that HsTX1[R14A] represents a valuable lead for conditions treatable by blockade of the voltage-gated potassium channel Kv1.3. The pharmacokinetics shows that both intravenous and subcutaneous applications are viable routes for the delivery of this potent peptide.
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Affiliation(s)
- Ralf Bergmann
- Helmholtz-Zentrum Dresden - Rossendorf, Institute of Radiopharmaceutical Cancer Research, Dresden, D-01328, Germany
| | - Manja Kubeil
- Helmholtz-Zentrum Dresden - Rossendorf, Institute of Radiopharmaceutical Cancer Research, Dresden, D-01328, Germany.,School of Chemistry, Monash University, Melbourne, Victoria, 3800, Australia
| | - Kristof Zarschler
- Helmholtz-Zentrum Dresden - Rossendorf, Institute of Radiopharmaceutical Cancer Research, Dresden, D-01328, Germany
| | - Sandeep Chhabra
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia
| | - Rajeev B Tajhya
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Christine Beeton
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA
| | | | - Michael Bachmann
- Helmholtz-Zentrum Dresden - Rossendorf, Institute of Radiopharmaceutical Cancer Research, Dresden, D-01328, Germany
| | - Raymond S Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia.
| | - Holger Stephan
- Helmholtz-Zentrum Dresden - Rossendorf, Institute of Radiopharmaceutical Cancer Research, Dresden, D-01328, Germany.
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Kuo YC, Hsu YR. Tissue-engineered polyethylene oxide/chitosan scaffolds as potential substitutes for articular cartilage. J Biomed Mater Res A 2009; 91:277-87. [DOI: 10.1002/jbm.a.32268] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Wilson JR, Duncan NA, Giles WR, Clark RB. A voltage-dependent K+ current contributes to membrane potential of acutely isolated canine articular chondrocytes. J Physiol 2004; 557:93-104. [PMID: 15020698 PMCID: PMC1665044 DOI: 10.1113/jphysiol.2003.058883] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2003] [Accepted: 03/10/2004] [Indexed: 11/08/2022] Open
Abstract
The electrophysiological properties of acutely isolated canine articular chondrocytes have been characterized using patch-clamp methods. The 'steady-state' current-voltage relationship (I-V) of single chondrocytes over the range of potentials from -100 to +40 mV was highly non-linear, showing strong outward rectification positive to the zero-current potential. Currents activated at membrane potentials negative to -50 mV were time independent, and the I-V from -100 to -60 mV was linear, corresponding to an apparent input resistance of 9.3 +/- 1.4 G Omega (n= 23). The outwardly rectifying current was sensitive to the K(+) channel blocking ion tetraethylammonium (TEA), which had a 50% blocking concentration of 0.66 mM (at +50 mV). The 'TEA-sensitive' component of the outwardly rectifying current had time- and membrane potential-dependent properties, activated near -45 mV and was half-activated at -25 mV. The reversal potential of the 'TEA-sensitive' current with external K(+) concentration of 5 mm and internal concentration of 145 mM, was -84 mV, indicating that the current was primarily carried by K(+) ions. The resting membrane potential of isolated chondrocytes (-38.1 +/- 1.4 mV; n= 19) was depolarized by 14.8 +/- 0.9 mV by 25 mM TEA, which completely blocked the K(+) current of these cells. These data suggest that this voltage-sensitive K(+) channel has an important role in regulating the membrane potential of canine articular chondrocytes.
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Affiliation(s)
- Jim R Wilson
- Department of Civil Engineering and Joint Injury and Arthritis Research Group, The University of Calgary, Calgary, Alberta, Canada T2N 4N1
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Farnum CE, Lee R, O'Hara K, Urban JPG. Volume increase in growth plate chondrocytes during hypertrophy: the contribution of organic osmolytes. Bone 2002; 30:574-81. [PMID: 11934648 DOI: 10.1016/s8756-3282(01)00710-4] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
During the differentiation cascade of growth plate chondrocytes, cells undergo as much as a 10-15-fold increase in volume. This volume increase, which occurs to different extents in growth plates growing at different rates, has been demonstrated to be the single most significant variable in understanding the quantitative aspects of the cellular kinetics of long bone growth. Our hypothesis is that this volume increase, which occurs through cell swelling by water imbibition, requires intracellular accumulation of osmolytes through activation or upregulation of membrane transport mechanisms. Significant intracellular accumulation of inorganic osmolytes, such as Na+, K+, and Cl-, is potentially disruptive to normal cellular metabolism, whereas intracellular accumulation of organic osmolytes is considered to be more compatible with metabolic function. Thus, we concentrated on determining the contributions of organic osmolytes--betaine, amino acids, inositol, and sorbitol--to volume increase. Pooled cryostat sections of young bovine growth plates were extracted followed by automated analysis for their content of amino acids. Analysis for betaine and the sugar alcohols was done by extraction and derivatization, followed by high-performance liquid chromatography (HPLC). Parallel stereological analyses correlated osmolyte changes to stages of chondrocytic differentiation, specifically comparing intracellular concentration and amount in proliferative vs. hypertrophic chondrocytes. Calculations demonstrated that, maximally, these organic osmolytes, in total, account for 6%-7% of the intracellular osmolytes required to sustain the volume increase, and that the most significant contribution is from betaine. This suggests that intracellular accumulation of organic osmolytes is not a primary strategy used by growth plate chondrocytes during volume increase of their terminal differentiation. The data also suggest that there is a differential regulation of transporters of these osmolytes such that intracellular concentrations are constantly modified as cells proceed through the differentiation cascade.
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Affiliation(s)
- C E Farnum
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, USA.
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